Lungen- und Atemwegsmedizin

Analysis of Short and Long Term Variability of Nasal Mucus versus Breath Condensate Inflammation Markers in Healthy Individuals

Abstract

Janssens Heleen, De Prins Sofie, Schoeters Greet and Koppen Gudrun

Objective: Inflammation markers were measured in nasal mucus and exhaled breath condensate (EBC) to assess the normal variability of these markers among healthy individuals. The measurement of protein markers in those matrices is valuable to provide information on inflammation endotypes and local reaction of the immune system.

Methods: Inflammation markers (IFN-γ, IL-1β, IL-8, IL-10, IL-13 and TNF-α) in nasal mucus and EBC from six healthy adults were measured by Meso Scale Discovery technology. Nasal mucus was collected with sponges of polyurethane foam, which is a recently developed sampling technique. EBC was sampled via an optimized breath manoeuver with the RTUBETM device. Both collections were done within a limited sampling time of two minutes. The samples were taken on the same day and within a time period of twenty days for the determination of short and long term variability, respectively.

Results: All inflammation markers were detectable in nasal mucus. This was in contrast with the measurements in EBC, in which only IFN-γ, IL-8 and IL-13 were detectable in the majority of the samples. EBC collected with the applied breathing technique gave a repeatable almost constant volume (448 μL (95% CI: 429 to 467 μL)). The collected volume of nasal mucus was more variable (from 0 to 200 μL). The variability of nasal analytes was similar over the short and long time period. The nasal inflammation marker levels were more stable within an individual than between different individuals (0.72 ≤ ICC ≤ 0.96). This was in contrast with the measurements in EBC that were highly variable over time (0.08 ≤ ICC ≤ 0.51).

Conclusion: We indicate – given the good detectability and low variability of the inflammation markers determined in nasal mucus – that nasal mucus, more than EBC, is potentially a good matrix to assess inflammation in the respiratory system.